Curable Compositions Comprising Adhesion Promoters

ABSTRACT

The invention relates to curable compositions based on curable polymers containing a special capped adhesion promoter, and optionally a curing catalyst. These compositions have improved adhesion properties and excellent storage stability. The invention also relates to the uses thereof.

The invention relates to curable compositions that comprise a cappedadhesion promoter. These compositions have improved adhesion propertiesand excellent storage stability. The invention relates furthermore tothe use thereof.

It is generally desirable that curable compositions that are used asadhesives, sealants and coatings have excellent adhesion to thesubstrates. To meet this need, various adhesion promoters are known inthe art. However, many formulations still show undesired limitations intheir properties, such as overall adhesion profile and their aging andstorage stability. Thus, there is still need in the art for formulationsthat show a good adhesion profile while at the same time beingsufficiently stable over extended periods of time.

Polymer systems which possess reactive crosslinkable silyl groups, forexample alkoxysilyl groups, have long been known. In the presence ofatmospheric moisture these alkoxysilane-terminated polymers are able tocondense with elimination of the alkoxy groups. Depending on the amountof alkoxysilane groups and their structure, mainly long-chain polymers(thermoplastics), relatively wide-meshed three-dimensional networks(elastomers) or highly crosslinked systems (thermosets) form.

Silicone polymers (polyorganosiloxanes), particularlypolydialkylsiloxanes such as polydimethylsiloxane (PDMS), have greatimportance in the production of adhesive, sealing, coating, andinsulation materials. Among these, those that vulcanize at lowtemperatures and under ambient conditions constitute a significant shareof the market. Typical formulations contain a reactivepolyorganosiloxane, in particular a silanol-terminatedpolyorganosiloxane having at least one, preferably two hydroxy groupsbound to a silicon atom. It is typically used in combination with asilane-based crosslinker which has hydrolyzable groups bound to thesilicon atom. While the polyorganosiloxane and crosslinker can bepresent as separate components, both can also be reacted with each otherto form a modified polyorganosiloxane which can then be used in acurable composition. The term endcapping (end group capping) is alsoused in this regard. This can be carried out optionally in the presenceof a catalyst, whereby the catalyst is to mediate the endcappingselectively without simultaneously curing the polyorganosiloxane.

The uses and possible applications of such silane-terminated polymersystems are equally diverse. They can, for example be used for theproduction of elastomers, sealants, adhesives, elastic adhesive systems,rigid and flexible foams, a wide variety of coating systems and in themedical field, for example, for impression materials in dentistry. Theseproducts can be applied in any form, such as painting, spraying,casting, pressing, filling and the like.

Numerous crosslinkers that act as endcapping or functionalizing moietiesfor the respective polymer backbone are known in the art. Besides theirfunctionality used for coupling to the polymer backbone, these can bedifferentiated into acidic, basic, and neutral crosslinkers based on thetype of leaving groups released during hydrolysis. Typical acidiccrosslinkers contain acid groups as hydrolyzable groups and release thecorresponding acids, e.g., acetic acid, during the crosslinking. Typicalbasic crosslinkers release amines during the crosslinking. In bothcases, aggressive compounds are released during the crosslinking, whichcan corrode or break down, e.g., metals, stone, or mortar, and whichmoreover have an intense, often unpleasant odor. Neutral crosslinkersare therefore often used for modern curable silicone compositions.Typical representatives of neutral crosslinkers have hydrolyzablegroups, which release alcohols or oximes during the crosslinking, suchas methanol or ethanol.

Such alkoxy systems nevertheless have the disadvantage that multipleproblems arise in the case of the storage stability of relevant curablecompositions and the cured products exhibit only poor adhesion to somematerials. Oximosilane crosslinkers, which hydrolyze with the release ofan alkanone oxime, usually do not have these disadvantages and aretherefore widely used. The most common representative of the oximosilanecrosslinkers releases butan-2-one oxime upon crosslinking. This compoundis however suspected of causing cancer so that there is an urgent needfor alternative neutral crosslinkers. Apart from that, the releasedoximes also have an intense, foul odor and working with curablecompositions, which contain such crosslinker, is perceived asdisagreeable by the users.

Silane compounds that release α-hydroxycarboxylic acid esters orα-hydroxycarboxylic acid amides during crosslinking, have already beenproposed therefore as alternative crosslinkers.

The preparation of suitable silane compounds has been long known and isdescribed, for example, by M. M. Sprung in “Someα-carbalkoxyalkoxysilanes,” J. Org. Chem., 1958, 23 (10), pp. 1530-1534.

DE 32 10 337 A1 as well discloses relevant silane compounds and thepreparation and use thereof in curable compositions based onpolydiorganosiloxanes, which have condensable end groups.

Hardeners for silicone rubber materials, which have three2-hydroxypropionic acid alkyl ester groups, i.e., lactic acid alkylester groups, are known from EP 2 030 976 A1. Vinyl tris(ethyllactato)silane is particularly preferred in this case.

EP 2 774 672 A1 describes special catalysts for the crosslinking ofsilicone rubber materials with a crosslinker based on a silane compoundwith lactate groups. Then again, the crosslinker can be the compoundsknown from EP 2 030 976 A1. Crosslinkers are also disclosed, however,which have only one, two, or also four 2-hydroxypropionic acid alkylester groups.

Although the use of a crosslinker based on a silane compound withlactate groups or similar α-carbalkoxyalkoxy groups is associated withmany advantages, the resulting formulations sometimes suffer from onlymoderate adhesion on certain challenging substrates, such as plasticsand concrete. Another challenge is to formulate curable silicone-basedcompositions containing these crosslinkers that exhibit good storagestability, as the storage stability may decrease specifically in thepresence of other conventional and frequently indispensable componentsof such compositions, particularly of curing catalysts and adhesionpromoters.

While some formulations that address some of these issues exist, it isan object of the present invention to provide alternative curablecompositions based on polyorganosiloxanes which allow the use ofcrosslinkers, releasing mainly hydroxycarboxylic acid esters—and aspossible byproducts hydroxycarboxylic acid amides—during crosslinking,and nevertheless still have a good adhesion and excellent storagestability.

The present invention achieves said object by providing curablecompositions, including but not limited to those based on specificpolyorganosiloxanes, i.e. polyorganosiloxanes endcapped with specificsilane groups, whereby the compositions contain at least one specificadhesion promoter and optionally at least one curing catalyst.

It has been found that the combination of the curable polymer systems asdisclosed herein with the specific adhesion promoters provides forexcellent storage stability while retaining good curing and adhesionproperties.

In a first aspect, the present invention therefore relates to a curablecomposition comprising or consisting essentially of:

(A) at least one curable polymer(B) at least one capped adhesion promoter of formula (I):

B—R¹¹—SiR¹² _(q)(OR¹³)_(3-q)   (I)

whereinR¹¹ is a linear or branched alkylene group, optionally interrupted by aheteroatom, preferably selected from O, NR¹⁴, S and Si(R¹⁴)₂, preferablyC₁-C₁₀ alkylene, more preferably C₁ or C₃ alkylene;each R¹² is independently selected from the group consisting ofhydrogen, halogen, amino, a substituted or unsubstituted alkyl, alkenyl,alkynyl, cycloaliphatic, aryl, heteroaryl, and heteroalicyclic group ora combination thereof;each R¹³ is independently selected from the group consisting of asubstituted or unsubstituted alkyl, alkenyl, alkynyl, or acyl group;each R¹⁴ is independently selected from the group consisting ofhydrogen, alkyl, alkenyl, alkynyl, cycloaliphatic, aryl, heteroaryl, andheteroalicyclic group or a combination thereof; q independently standsfor 0, 1, or 2; andB is a nitrogen-containing group of formula (1)

—NR¹⁵R¹⁶   (1)

whereinR¹⁵ is selected from —Si(R¹⁷)₃;R¹⁶ is selected from —Si(R¹⁷)₃, hydrogen, a substituted or unsubstitutedalkyl, alkenyl, alkynyl, cycloaliphatic, aryl, heteroaryl, andheteroalicyclic group or a combination thereof; andeach R¹⁷ is independently selected from hydrogen, a substituted orunsubstituted alkyl, alkenyl, alkynyl, cycloaliphatic, or aryl group ora combination thereof; or wherein R¹⁵ and R¹⁶ combine to form togetherwith the nitrogen atom to which they are attached a group of formula—Si(R¹⁷)₂—R¹⁸—Si(R¹⁷)₂—, wherein R¹⁸ is a linear or branched alkylenegroup, preferably C₂ or C₃ alkylene; and(C) optionally at least one curing catalyst.

The invention further relates to the use of a curable composition of theinvention or a curable composition prepared according to the method ofthe invention as an adhesive, sealing, or coating material.

A “curable composition” is understood to be a substance or mixture ofmultiple substances, which is curable by physical or chemical measures.In this regard, these chemical or physical measures can be, for example,the supplying of energy in the form of heat, light, or otherelectromagnetic radiation, but also simply bringing into contact withatmospheric moisture, water, or a reactive component. The compositionthereby changes from an original state to a state that has a higherhardness. In various embodiments, the curable compositions are moisturecurable compositions. In such embodiments, the term “curable” mayparticularly relate to the property of (terminal) silane groupscontained in the polymers to condensate.

Provided reference is made to molecular weights of oligomers or polymersin the present application, the quantities, unless otherwise stated,refer to the weight average, i.e., the M_(w) value, and not to thenumber average molecular weight. The molecular weight is determined bygel permeation chromatography (GPC) with tetrahydrofuran (THF) as theeluent according to DIN 55672-1:2007-08, preferably at 35° C. Molecularweights of monomeric compounds are calculated based on the respectivemolecular formula and the known molecular weights of the individualatoms.

“At least one,” as used herein, refers to 1 or more, i.e., 1, 2, 3, 4,5, 6, 7, 8, 9, or more. In regard to an ingredient, the term relates tothe type of ingredient and not to the absolute number of molecules. “Atleast one polymer” thus means, for example, at least one type ofpolymer, i.e., that a type of polymer or a mixture of a number ofdifferent polymers can be used. Together with weight data, the termrefers to all compounds of the given type, contained in thecomposition/mixture, i.e., that the composition contains no othercompounds of this type beyond the given amount of the relevantcompounds.

All percentage data, provided in connection with the compositionsdescribed herein, refer to % by weight, based in each case on therelevant mixture, unless explicitly indicated otherwise.

“Consisting essentially of”, as used herein, means that the respectivecomposition is composed mainly, i.e. by at least 50% by weight, forexample at least 60, 70 or 80%, of the listed components (A), (B) andoptionally (C) and as well as optional other additives, such as fillersand/or plasticizers, as described below.

“About”, as used herein in relation to numerical values means thereferenced value ±10%, preferably ±5%.

“Alkyl,” as used herein, refers to a saturated aliphatic hydrocarbonincluding straight-chain and branched-chain groups. The alkyl grouppreferably has 1 to 10 carbon atoms (if a numerical range, e.g., “1-10”is given herein, this means that this group, in this case the alkylgroup, can have 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc., upto and including 10 carbon atoms). In particular, the alkyl can be anintermediate alkyl, which has 5 to 6 carbon atoms, or a lower alkyl,which has 1 to 4 carbon atoms, e.g., methyl, ethyl, n-propyl, isopropyl,butyl, isobutyl, tert-butyl, etc. The alkyl groups can be substituted orunsubstituted. “Substituted,” as used in this connection, means that oneor more carbon atoms and/or hydrogen atom(s) of the alkyl group arereplaced by heteroatoms or functional groups. Functional groups that canreplace the hydrogen atoms are selected particularly from ═O, ═S, —OH,—SH, —NH₂, —N(Alk)₂, —NO₂, —CN, —F, —Cl, —Br, —I, —COON, —CONH₂, —OCN,—NCO, C₃₋₈ cycloalkyl, C₆₋₁₄ aryl, a 5-10-membered heteroaryl ring, inwhich 1 to 4 ring atoms independently are nitrogen, oxygen, or sulfur,and a 5-10-membered heteroalicyclic ring, in which 1 to 3 ring atoms areindependently nitrogen, oxygen, or sulfur. “Alk”, as used herein, meansan unsubstituted C₁₋₁₀ alkyl group, preferably lower alkyl, i.e. C₁₋₄alkyl, more preferably methyl or ethyl. Substituted alkyl includes, forexample, alkylaryl and aminoalkyl groups, includingN,N-dialkylaminoalkyl groups. Heteroalkyl groups in which 1 or morecarbon atoms are replaced by heteroatoms, particularly selected from O,S, N, and Si, are obtained by the replacement of one or more carbonatoms by heteroatoms. Examples of such heteroalkyl groups are, withoutlimitation, methoxymethyl, ethoxyethyl, propoxypropyl, methoxyethyl,isopentoxypropyl, ethylaminoethyl, trimethoxypropylsilyl, etc.

“Alkenyl,” as used herein, refers to an alkyl group, as defined herein,which consists of at least two carbon atoms and at least onecarbon-carbon double bond, e.g., ethenyl, propenyl, butenyl, or pentenyland structural isomers thereof such as 1- or 2-propenyl, 1-, 2-, or3-butenyl, etc. Alkenyl groups can be substituted or unsubstituted. Ifthey are substituted, the substituents are as defined above for alkyl.“Alkenyloxy” refers to an alkenyl group, as defined herein, that islinked via an —O— to the rest of the molecule. The respective term thusincludes enoxy groups, such as vinyloxy (H₂C═CH—O—).

“Alkynyl,” as used herein, refers to an alkyl group, as defined herein,which consists of at least two carbon atoms and at least onecarbon-carbon triple bond, e.g., ethynyl (acetylene), propynyl, butynyl,or petynyl and structural isomers thereof as described above. Alkynylgroups can be substituted or unsubstituted. If they are substituted, thesubstituents are as defined above for alkyl. “Alkylnyloxy” refers to analkynyl group, as defined herein, that is linked via an —O— to the restof the molecule.

A “cycloaliphatic group” or “cycloalkyl group,” as used herein, refersto monocyclic or polycyclic groups (a number of rings with carbon atomsin common), particularly of 3-8 carbon atoms, in which the ring does nothave a completely conjugated pi-electron system, e.g., cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, cyclobutenyl, cyclopentenyl,cyclohexenyl, etc. Cycloalkyl groups can be substituted orunsubstituted. “Substituted,” as used in this regard, means that one ormore hydrogen atoms of the cycloalkyl group are replaced by functionalgroups. Functional groups that can replace the hydrogen atoms areselected particularly from ═O, ═S, —OH, —SH, —NH₂, —NO₂, —CN, —F, —Cl,—Br, —I, —COOH, —CONH₂, —OCN, —NCO, C₁₋₁₀ alkyl, C₂₋₁₀ alkenyl, C₂₋₁₀alkynyl, C₃₋₈ cycloalkyl, C₆₋₁₄ aryl, a 5-10-membered heteroaryl ring,in which 1 to 4 ring atoms independently are nitrogen, oxygen, orsulfur, and a 5-10-membered heteroalicyclic ring, in which 1 to 3 ringatoms independently are nitrogen, oxygen, or sulfur. “Cycloalkyloxy”refers to a cycloalkyl group, as defined herein, that is linked via an—O— to the rest of the molecule.

“Aryl,” as used herein, refers to monocyclic or polycyclic groups (i.e.,rings that have neighboring carbon atoms in common), particularly of 6to 14 carbon ring atoms which have a completely conjugated pi-electronsystem. Examples of aryl groups are phenyl, naphthalenyl, andanthracenyl. Aryl groups can be substituted or unsubstituted. If theyare substituted, the substituents are as defined above for cycloalkyl.“Aryloxy” refers to an aryl group, as defined herein, that is linked viaan —O— to the rest of the molecule.

A “heteroaryl” group, as used herein, refers to a monocyclic orpolycyclic (i.e., rings that share an adjacent ring atom pair) aromaticring, having particularly 5 to 10 ring atoms, where one, two, three, orfour ring atoms are nitrogen, oxygen, or sulfur and the rest is carbon.Examples of heteroaryl groups are pyridyl, pyrrolyl, furyl, thienyl,imidazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyrazolyl,1,2,3-triazolyl, 1,2,4-triazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl,1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, 1,3,4-triazinyl, 1,2,3-triazinyl,benzofuryl, isobenzofuryl, benzothienyl, benzotriazolyl,isobenzothienyl, indolyl, isoindolyl, 3H-indolyl, benzimidazolyl,benzothiazolyl, benzoxazolyl, quinolizinyl, quinazolinyl, phthalazinyl,quinoxalinyl, cinnolinyl, naphthyridinyl, quinolyl, isoquinolyl,tetrazolyl, 5,6,7,8-tetrahydroquinolyl, 5,6,7,8-tetrahydroisoquinolyl,purinyl, pteridinyl, pyridinyl, pyrimidinyl, carbazolyl, xanthenyl, orbenzoquinolyl. Heteroaryl groups can be substituted or unsubstituted. Ifthey are substituted, the substituents are as defined above forcycloalkyl. “(Hetero)aryl”, as used herein, refers to both aryl andheteroaryl groups as defined herein. “Heteroaryloxy” refers to aheteroaryl group, as defined herein, that is linked via an —O— to therest of the molecule.

A “heteroalicyclic group” or a “heterocycloalkyl group,” as used herein,refers to a monocyclic or fused ring having 5 to 10 ring atoms, whichcontains one, two, or three heteroatoms, selected from N, O, and S,whereby the rest of the ring atoms are carbon. A “heterocycloalkenyl”group contains in addition one or more double bonds. The ring howeverhas no completely conjugated pi-electron system. Examples ofheteroalicyclic groups are pyrrolidinone, piperidine, piperazine,morpholine, imidazolidine, tetrahydropyridazine, tetrahydrofuran,thiomorpholine, tetrahydropyridine, and the like. Heterocycloalkylgroups can be substituted or unsubstituted. If they are substituted, thesubstituents are as defined above for cycloalkyl. “Heteroalicyclic”refers to a heteroalicyclic group, as defined herein, that is linked viaan —O— to the rest of the molecule.

The curable compositions of the invention contain as component (A) atleast one curable polymer. In various embodiments, said curable polymermay be selected from the group consisting of silane-modified polymers(SMPs), silicones, polyurethanes, and epoxides.

In various embodiments, the curable polymer is a silicone. Preferred aresilicone polymers that comprise or consist essentially of at least onepolyorganosiloxane, such as polydimethylsiloxane. In variousembodiments, said polymers may contain at least one terminal group ofthe formula (II):

-A-Si(R¹)_(m)(R²)_(n)(R³)_(3-(m+n))   (II)

wherein:A is a bond, —O— or a linear, branched or cyclic divalent group selectedfrom hydrocarbon residues having 1 to 12 carbon atoms, alkylene,arylene, oxyalkylene, oxyarylene, siloxane-alkylene, siloxane-arylene,ester, amine, glycol, imide, amide, alcohol, carbonate, urethane, urea,sulfide, ether or a derivative or combination thereof;each R¹ is independently selected from the group consisting of hydrogen,halogen, amino, oximino, a substituted or unsubstituted alkyl, alkenyl,alkenyloxy, alkynyl, alkylnyloxy, cycloaliphatic, cycloaliphatic-O-,aryl, aryloxy, heteroaryl, heteroaryloxy, heteroalicyclic,heteroalicyclicoxy, acyl, acyloxy group or a combination thereof;each R² is independently a group of the general formula (2):

—O—Y—COOR⁴   (2)

whereinY is a substituted or unsubstituted (hetero)aromatic group having 4 to14 ring atoms, a substituted or unsubstituted saturated or partiallyunsaturated 4- to 14-membered (hetero)cyclic group or —(C(R⁵)₂)_(o)—;R⁴ is a substituted or unsubstituted alkyl, alkenyl, alkynyl,cycloaliphatic, aryl, heteroaryl, and heteroalicyclic group or acombination thereof;each R⁵ is independently selected from the group consisting of hydrogen,a substituted or unsubstituted alkyl, alkenyl, alkynyl, cycloaliphaticor aryl group; and o is an integer from 1 to 10;each R³ independently is a group of the general formula (3):

—O—Y—CONR⁶R⁷   (3)

whereinY is as defined above;R⁶ is selected from the group consisting of hydrogen, a substituted orunsubstituted alkyl, alkenyl, alkynyl cycloaliphatic, aryl, heteroaryl,and heteroalicyclic group or a combination thereof or R⁷;R⁷ is a group of the general formula (4):

—R⁸—SiR⁹ _(p)(OR¹⁰)_(3-p)   (4)

whereinR⁸ is an alkylene group, optionally interrupted by a heteroatom, such asO, N, S or Si; each R⁹ is independently selected from the groupconsisting of hydrogen, halogen, amino, a substituted or unsubstitutedalkyl, alkenyl, alkynyl, cycloaliphatic, aryl, heteroaryl, andheteroalicyclic group or a combination thereof;each R¹⁰ is independently selected from the group consisting of asubstituted or unsubstituted alkyl, alkenyl, alkynyl, or acyl group;each p independently stands for 0, 1, or 2;m is independently 0, 1 or 2; andn is independently 1, 2, or 3, wherein the sum n+m is a maximum of 3;

It has been found that the combination of the polyorganosiloxaneendcapped with a silyl group having hydroxycarboxylic acid esters or toa lesser degree hydroxycarboxylic acid amides as leaving groups bound tothe silicon atom and the adhesion promoter having a protected aminofunctionality that only gets released upon contact with moisture/waterassures that the curable composition has very high storage stability andcures reliably and at a sufficient rate after application in thepresence of atmospheric moisture even at room temperature (23° C.).

According in various embodiments, the curable polymers include apolyorganosiloxane endcapped with silane groups of formula (II). Suchpolymers are obtainable by providing at least one polyorganosiloxane,which has at least one hydroxy group bound to a silicon atom.Preferably, the polyorganosiloxane has at least two hydroxy groups boundto a silicon atom. It is preferred, in addition, that the hydroxy groupor hydroxy groups are bound to terminal silicon atoms. If thepolyorganosiloxane is branched, it preferably has a hydroxy group ateach end. Accordingly, while the invention covers polymers that have thesilane group of formula (II) only on one end, it is preferred that allpolymer chain ends are endcapped by said groups, i.e. a linear polymerwould thus have two terminal silane groups. If the polymer is branched,it is preferred that each end is endcapped with the groups of formula(II).

The polyorganosiloxane, which has at least one hydroxy group bound to asilicon atom, is preferably a polydiorganosiloxane, preferably apolydimethylsiloxane.

Preferably, therefore, an α,ω-dihydroxy-terminated polydiorganosiloxane,particularly an α,ω-dihydroxy-terminated polydimethylsiloxane is used asthe polyorganosiloxane, which has at least one hydroxy group bound to asilicon atom. Particularly preferred are α,ω-dihydroxy-terminatedpolydimethylsiloxanes, which have a kinematic viscosity at 25° C. of5000 to 120,000 cSt, particularly 10,000 to 100,000 cSt, andparticularly preferably 50,000 to 90,000 cSt.

The polyorganosiloxanes may be linked to the terminal groups of formula(II) via a variety of different linking groups A. In variousembodiments, A is a direct covalent bond, —O—, oxyalkylene, such as—O—CH₂— or —O—(CH₂)₃— or a linear or branched divalent group selectedfrom siloxane-alkylene, preferably of the formula—(CH₂)₁₋₁₀—(Si(Alk)₂—O—Si(Alk)₂)₁₋₁₀—(CH₂)₁₋₁₀, or a derivative thereof,with Alk being unsubstituted C₁₋₁₀ alkyl, preferably methyl. If A is asiloxane-alkylene of the formula—(CH₂)₁₋₁₀—(Si(Alk)₂—O—Si(Alk)₂)₁₋₁₀—(CH₂)₁₋₁₀, it is preferablyselected from —(CH₂)₂—Si(CH₃)₂—O—Si(CH₃)₂—(CH₂)₂—.

Alternatively, in various embodiments, the polyorganosiloxanes may belinked to the terminal groups of formula (II) via a moiety selected from—O—C(═O)—NH—, —NH—C(═O)O—, —NH—C(═O)—NH—, —NR—C(═O)—NH—, —NH—C(═O)—NR′—,—NH—C(═O)—, —C(═O)—NH—, —C(═O—O—, —O—C(O)—, —O—C(═O)—O—, —S—C(═O)—NH—,—NH—C(═O)—S—, —C(═O)—S—, —S—C(═O)—, —S—C(═O)—S—, —C(═O)—, —S—, —O—, and—NR′—, wherein R′ can be hydrogen or a hydrocarbon moiety with 1 to 6carbon atoms, optionally substituted with halogen, preferably C₁-C₂alkyl or hydrogen. In such embodiments, A may consist of theafore-mentioned groups optionally further connected to a bivalentalkylene group having 1 to 10 carbon atoms, optionally interrupted by aheteroatom, that may be substituted, preferably —CH₂— or —(CH₂)₃—. Ifsuch alkylene group is present, the orientation is such that thealkylene group connects to the silicon atom of the terminal group offormula (H) while the above-listed functional groups connect to aterminal silicon atom of the polymer chain, i.e. the full linker -A-could be —O—C(═O)—NH—C₁₋₁₀ alkylene- or alkylene-.

To obtain a polymer (A), said polymers may be reacted with a suitablesilane crosslinker that yields the desired polymer (A). Generally, saidcrosslinkers are silanes of the formula:

C—Si(R¹)_(m)(R²)_(n)(R³)_(3-(m+n))

with C being the reactive group that reacts with the terminal group ofthe polymer, typically —OH or amino or isocyanate, to yield the linkinggroup -A-.

Suitable reactions are known and are also called endcapping. These canbe carried out optionally in the presence of a catalyst, whereby thecatalyst is to mediate the endcapping selectively without simultaneouslycuring the polyorganosiloxane. Suitable catalysts are, for example,acids, organic lithium compounds, as they are described, for example, inEP 0 564 253 A1, amines, inorganic oxides, potassium acetate,organotitanium derivatives, titanium/amine combinations, and carboxylicacid/amine combinations.

In the group of formula (II), each R¹ independently stands for asubstituted or unsubstituted alkyl, alkenyl, or alkynyl group; asubstituted or unsubstituted cycloaliphatic group or aryl group; or asubstituted or unsubstituted heteroalicyclic group or heteroaryl group.Alternatively or additionally, one or more R¹ may represent hydrogen,halogen, amino, oximino, alkenyloxy, alkylnyloxy, cycloaliphatic-O—,aryloxy, heteroaryloxy, heteroalicyclicoxy, acyl, acyloxy or acombination thereof.

In various embodiments, each R¹ independently of one another stands foran alkyl group having 1 to 10 carbon atoms, particularly methyl, ethyl,propyl, or isopropyl, for an alkenyl group having 2 to 10 carbon atoms,particularly vinyl or allyl, or an aryl group having 6 to 10 carbonatoms, particularly phenyl, or an aryloxy group having 6 to 14 carbonatoms, or an acyloxy group having 2 to 10 carbon atoms, preferablyacetoxy, oximino, alkenyloxy having 2 to 10 carbon atoms, or amino.

In specific embodiments, each R¹ independently represents methyl, vinyl,or phenyl, particularly preferred are methyl and vinyl.

In formula (II), each R² independently represents a group of the generalformula (2):

—O—Y—COOR⁴   (2)

whereinY is a substituted or unsubstituted (hetero)aromatic group having 4 to14 ring atoms, a substituted or unsubstituted saturated or partiallyunsaturated 4- to 14-membered (hetero)cyclic group or —C(R⁵)₂)_(o)—;R⁴ is a substituted or unsubstituted alkyl, alkenyl, alkynyl,cycloaliphatic, aryl, heteroaryl, and heteroalicyclic group or acombination thereof; each R⁵ is independently selected from the groupconsisting of hydrogen, a substituted or unsubstituted alkyl, alkenyl,alkynyl, cycloaliphatic or aryl group; and o is an integer from 1 to 10,preferably 1 to 5, more preferably 1 or 2.

In various embodiments, each R² independently of one another stands fora group of the formula (2), wherein R⁴ stands for a substituted orunsubstituted alkyl group having 1 to 10 carbon atoms, particularlyhaving 1 to 4 carbon atoms, particularly preferably methyl or ethyl. Insome embodiments, Y is a substituted or unsubstituted aromatic grouphaving 6 carbon ring atoms, preferably 1,2-phenylene, or —(C(R⁵)₂)_(o)—,wherein o is 1 and one of the R⁵ groups is hydrogen and the second R⁵group is a substituted or unsubstituted alkyl group having 1 to 10carbon atoms, particularly methyl, carboxymethyl or an (alkyl) esterthereof, such as ethylcarboxymethyl.

In various embodiments, each R² independently of one another stands fora lactic acid ester, preferably the ethyl ester, or a malic acid mono-or diester, preferably the mono- or diethyl ester.

In other embodiments, each R² is derived from salicylic acid, i.e. Y is1,2-phenylene. The salicylic acid residue is an ester, for example themethyl or ethyl ester, preferably the ethyl ester.

In various embodiments, each R³ independently of one another stands fora group of the general formula (3):

—O—Y—CONR⁶R⁷   (3)

In various embodiments, Y is as defined above; R⁶ is selected from thegroup consisting of hydrogen, a substituted or unsubstituted alkyl,alkenyl, alkynyl cycloaliphatic, aryl, heteroaryl, and heteroalicyclicgroup or a combination thereof or R⁷; and R⁷ is a group of the generalformula (4):

—R⁸—SiR⁹ _(p)(OR¹⁰)_(3-p)   (4)

whereinR⁸ is an alkylene group, optionally interrupted by a heteroatom, such asO, N, S or Si, preferably a C1-10 or C1-8 alkylene group, morepreferably a C1-C3 alkylene group, most preferably a methylene (CH₂) orpropylene ((CH₂)₃) group;each R⁹ is independently selected from the group consisting of hydrogen,halogen, amino, a substituted or unsubstituted alkyl, alkenyl, alkynyl,cycloaliphatic, aryl, heteroaryl, and heteroalicyclic group or acombination thereof;each R¹⁰ is independently selected from the group consisting of asubstituted or unsubstituted alkyl, alkenyl, alkynyl, or acyl group,preferably unsubstituted lower alkyl, more preferably methyl or ethyl;andeach p independently stands for 0, 1, or 2, preferably 0 or 1, morepreferably 0.

In various embodiments, in the groups of formula (3) the Y is as definedfor the group of formula (2) above, i.e. Y is a substituted orunsubstituted aromatic group having 6 carbon ring atoms, preferably1,2-phenylene, or —(C(R⁵)₂)_(o)—, wherein o is 1 and one of the R⁵groups is hydrogen and the second R⁵ group is a substituted orunsubstituted alkyl group having 1 to 10 carbon atoms, particularlymethyl, carboxymethyl or an (alkyl) ester thereof, such asethylcarboxymethyl.

In various embodiments, R⁶ preferably stands for hydrogen, a substitutedor unsubstituted alkyl group having 1 to 10 carbon atoms, preferably anunsubstituted alkyl group having 1 to 10 carbon atoms, more preferablyhaving 1 to 6 carbon atoms, even more preferably unsubstituted alkylhaving 1 to 4 carbon atoms or hydrogen.

In various embodiments, R⁸ preferably is an alkylene group of theformula —(CH₂)₁₋₈—, more preferably —(CH₂)₁₋₅—, even more preferably—(CH₂)₁₋₃—, most preferably —CH₂— or —(CH₂)₃—.

In various embodiments, each R⁹ independently of one another preferablystands for a substituted or unsubstituted alkyl group having 1 to 10carbon atoms, preferably an unsubstituted alkyl group having 1 to 10carbon atoms, particularly having 1 to 4 carbon atoms, particularlypreferably methyl or ethyl.

In various embodiments, each R¹⁰ independently of one another preferablystands for a substituted or unsubstituted alkyl group having 1 to 10carbon atoms, preferably an unsubstituted alkyl group having 1 to 10carbon atoms, particularly having 1 to 4 carbon atoms, particularlypreferably methyl or ethyl, most preferably methyl.

Preferably each R³ independently of one another stands for a group ofthe formula (3), wherein Y is a substituted or unsubstituted aromaticgroup having 6 carbon ring atoms, preferably 1,2-phenylene, or—C(R⁵)₂)_(o)—, wherein o is 1 and one of the R⁵ groups is hydrogen andthe second R⁵ group is a substituted or unsubstituted alkyl group having1 to 10 carbon atoms, particularly methyl, carboxymethyl or an (alkyl)ester thereof, R⁶ represents hydrogen, a substituted or unsubstitutedalkyl group having 1 to 10 carbon atoms, particularly having 1 to 4carbon atoms, and R⁷ represents a group of the formula (4), where R⁸ isa C1-10 alkylene group, preferably a C1 or C3 alkylene group, each R⁹independently of one another stands for a substituted or unsubstitutedalkyl group having 1 to 10 carbon atoms, particularly having 1 to 4carbon atoms, particularly preferably methyl or ethyl, and each R¹°independently of one another stands for a substituted or unsubstitutedalkyl group having 1 to 10 carbon atoms, particularly having 1 to 4carbon atoms, particularly preferably methyl or ethyl; and p is 0 or 1,preferably 0.

In a first embodiment, n and m in formula (II) are selected so that thesum n+m is 3. In this case, the silane of the formula (II) contains noR³ group, i.e., no hydroxycarboxylic acid amide group. Preferred silanegroups of the formula (II) in this case are selected from methylbis(ethyl lactato)silane, ethyl bis(ethyl lactato)silane, phenylbis(ethyl lactato)silane, vinyl bis(ethyl lactato)silane, tri(ethyllactato)silane, methyl bis(ethyl salicylato)silane, ethyl bis(ethylsalicylato)silane, phenyl bis(ethyl salicylato)silane, vinyl bis(ethylsalicylato)silane, tri(ethyl salicylato)silane, methyl bis(diethylmalato)silane, ethyl bis(diethyl malato)silane, phenyl bis(diethylmalato)silane, vinyl bis(diethyl malato)silane, tri(diethylmalato)silane and mixtures thereof.

In a second embodiment, n and m in formula (II) are selected so that thesum n+m is 2. In this case, the silane of the formula (II) contains atleast one R³ group, i.e., at least one hydroxycarboxylic acid amidegroup. Preferred silanes of the formula (II) in this case are selectedfrom compounds, which are obtained by the selective amidation of methylbis(ethyl lactato)silane, ethyl bis(ethyl lactato)silane, phenylbis(ethyl lactato)silane, vinyl bis(ethyl lactato)silane, tri(ethyllactato)silane, methyl bis(ethyl salicylato)silane, ethyl bis(ethylsalicylato)silane, phenyl bis(ethyl salicylato)silane, vinyl bis(ethylsalicylato)silane, tri(ethyl salicylato)silane, methyl bis(diethylmalato)silane, ethyl bis(diethyl malato)silane, phenyl bis(diethylmalato)silane, vinyl bis(diethyl malato)silane, tri(diethylmalato)silane, and mixtures thereof with an amine of the formula (5):

(HR⁶N)—R⁸—SiR⁹ _(p)(OR¹⁰)_(3-p)   (5)

wherep, R⁶, R⁸, R⁹ and R¹⁰, in each case independently of one another, havethe aforesaid general, preferred, and particularly preferred meanings.Particularly preferably, this concerns an amidation product of methylbis(ethyl lactato)silane, ethyl bis(ethyl lactato)silane, phenylbis(ethyl lactato)silane, vinyl bis(ethyl lactato)silane, tri(ethyllactato)silane, methyl bis(ethyl salicylato)silane, ethyl bis(ethylsalicylato)silane, phenyl bis(ethyl salicylato)silane, vinyl bis(ethylsalicylato)silane, tri(ethyl salicylato)silane, methyl bis(diethylmalato)silane, ethyl bis(diethyl malato)silane, phenyl bis(diethylmalato)silane, vinyl bis(diethyl malato)silane, tri(diethylmalato)silane, and mixtures thereof with 3-aminopropyltrimethoxysilaneand/or 3-aminopropyltriethoxysilane.

In various embodiments of the invention, the curable polymer may be asilane-modified polymer. Silane-modified polymers (SMPs) includepolymers that have terminal silane groups.

SMPs generally are comprised of flexible polymeric backbones that areterminated by moisture reactive (hydrolyzable) silane terminal groups.SMPs, generally, have been made by three routes. The first, illustratedby U.S. Pat. No. 3,971,751, involves hydrosilylating a silicon hydridehaving hydrolyzable silyl groups with an allyl terminated polyether,where the allyl terminated polyether was formed from a polyether polyol.The second, illustrated by U.S. Pat. No. 3,632,557, generally involvesreacting an am inosilane with an isocyanate terminated prepolymerresulting in trialkoxysilyl end groups with polyether polymer backbonescontaining urea linkages. The third, illustrated by U.S. Pat. Nos.4,625,012 and 6,355,127 involves reacting an isocyanato organosilanewith a polyurethane having terminal active hydrogens.

The terminal silane groups may be of formula (4), as defined above,i.e., have the formula —R⁸—SiR⁹ _(p)(OR¹⁰)_(3-p)), wherein R⁸ is analkylene group, optionally interrupted by a heteroatom, such as O, N, Sor Si; each R⁹ is independently selected from the group consisting ofhydrogen, halogen, amino, a substituted or unsubstituted alkyl, alkenyl,alkynyl, cycloaliphatic, aryl, heteroaryl, and heteroalicyclic group ora combination thereof; and each R¹⁰ is independently selected from thegroup consisting of a substituted or unsubstituted alkyl, alkenyl,alkynyl, or acyl group. Additionally, in one embodiment R⁸ may be absentso that the silicon atom is directly bonded to the polymer. Suitablechemistries for linking the silane group to the polymer backbone havebeen described by reference above and may be further adapted by thoseskilled in the art.

The polymer backbone may be any type of polymer suitable for thispurpose and includes polyurethanes, polyethers, polyesters, andpolycarbonates. Commercially available SMPs include those available fromDow under the tradename Vorasil® and from Evonik under the tradenamesPolymer ST and Tegopac®.

In various other embodiments, the curable polymer may be a polyurethane,in particular a polyurethane that is not silane-modified. Thepolyurethane may a 1K or 2K polyurethane composition. 1K polyurethanestypically comprise a latent hardener in a resin matrix, with thehardener getting activated upon certain conditions, such as by elevatedtemperatures, and then starting the curing reaction. In case thehardener is a polyisocyanate, the resin is a polyol or polyamine,typically a polyol, or a hydroxy or amine-terminated prepolymer. Invarious embodiments, the hardener may also comprise or consist of aNCO-terminated prepolymer, typically a NCO-terminated PU prepolymerobtainable by reaction of a polyol with a molar excess ofpolyisocyanate. Alternatively, PU compositions in which a polyol oramine is used as the hardener and the polyisocyanate or, morepreferably, an NCO-terminated prepolymer is used as the resin aresimilarly suitable. In the corresponding 2K compositions, the resin andthe hardener are separate (for example in separate containers) and mixeddirectly before use to avoid premature curing. In such 2K compositions,there is typically no need for latent hardeners.

Suitable isocyanate compounds for use in or for manufacture of thepolyurethanes and PU compositions described above, include all compoundsthat contain two or more isocyanate groups. Organic polyisocyanates,which may be used, include, without limitation, alkylene diisocyanates,cycloalkylene diisocyanates, aromatic diisocyanates andaliphatic-aromatic diisocyanates. Specific examples of suitableisocyanate-containing compounds include, but are not limited to,ethylene diisocyanate, ethylidene diisocyanate, propylene diisocyanate,butylene diisocyanate, trimethylene diisocyanate, hexamethylenediisocyanate, toluene diisocyanate, cyclopentylene-1,3-diisocyanate,cyclo-hexylene-1,4-diisocyanate, cyclohexylene-1,2-diisocyanate,4,4′-diphenylmethane diisocyanate,2,2-diphenylpropane-4,4′-diisocyanate, xylylene diisocyanate,1,4-naphthylene diisocyanate, 1,5-naphthylene diisocyanate, m-phenylenediisocyanate, p-phenylene diisocyanate, diphenyl-4,4′-diisocyanate,azobenzene-4,4′-diisocyanate, diphenylsulphone-4,4′-diisocyanate,2,4-tolylene diisocyanate, dichlorohexa-methylene diisocyanate,furfurylidene diisocyanate, 1-chlorobenzene-2,4-diisocyanate,4,4′,4″-triisocyanatotriphenylmethane, 1,3,5-triisocyanato-benzene,2,4,6-triisocyanato-toluene,4,4′-dimethyldiphenyl-methane-2,2′,5,5-tetratetraisocyanate, and thelike. While such compounds are commercially available, methods forsynthesizing such compounds are well known in the art. Preferredisocyanate-containing compounds are methylenebisphenyldiisocyanate (MDI)and its polymeric analog as described in “The Polyurethanes Book”, D.Randall and S. Lee, eds., John Wiley & Sons, 2002, page 84,isophoronediisocyanate (IPDI), hydrogenatedmethylenebisphenyldiisocyanate (HMDI) and toluene diisocyanate (TDI).

If the PU comprises a prepolymer, the polyisocyanate may be reacted inexcess with a polyol with regard to the molar NCO:OH ratio to produce anisocyanate-functional PU prepolymer. By selection of the molar NCO:OHratio it is possible to control the molecular weight and the amount ofreactive NCO groups in the prepolymer.

Suitable polyols include, without limitation, polyhydroxy ethers(substituted or unsubstituted polyalkylene ether glycols or polyhydroxypolyalkylene ethers), polyhydroxy polyesters, the ethylene or propyleneoxide adducts of polyols and the monosubstituted esters of glycerol, and“polymer polyols” (i.e., graft polyols containing a proportion of avinyl monomer, polymerized in situ) as well as mixtures thereof. Whilesuch compounds are commercially available, methods for synthesizing suchcompounds are well known in the art. In various embodiments of thepresent invention, the polyols are selected from polyester polyols,polyether polyol, and combination thereof.

Suitable polyether polyols include linear and/or branched polyethershaving plural numbers of ether bonds and at least two hydroxyl groups,and contain substantially no functional group other than the hydroxylgroups. Examples of the polyether polyol may include polyoxyalkylenepolyol such as polyethylene glycol, polypropylene glycol,polytetramethylene glycol, polybutylene glycol and the like. Further, ahomopolymer and a copolymer of the polyoxyalkylene polyols or mixturesthereof may also be employed. Particularly preferable copolymers of thepolyoxyalkylene polyols may include an adduct of at least one compoundselected from the group consisting of ethylene glycol, propylene glycol,diethylene glycol, dipropylene glycol, triethylene glycol,2-ethylhexanedio1-1,3,glycerin, 1,2,6-hexane triol, trimethylol propane,trimethylol ethane, tris(hydroxyphenyl)propane, triethanolamine,triisopropanolamine; with at least one compound selected from the groupconsisting of ethylene oxide, propylene oxide and butylene oxide. Whilesuch compounds are commercially available, methods for synthesizing suchcompounds are well known in the art.

Suitable polyester polyols may be formed from the condensation of one ormore polyhydric alcohols having from about 2 to about 15 carbon atomswith one or more polycarboxylic acids having from about 2 to about 14carbon atoms. Examples of suitable polyhydric alcohols include ethyleneglycol, propylene glycol such as 1,2-propylene glycol and 1,3-propyleneglycol, glycerol, pentaerythritol, trimethylolpropane,1,4,6-octanetriol, butanediol, pentanediol, hexanediol, dodecanediol,octanediol, chloropentanediol, glycerol monallyl ether, glycerolmonoethyl ether, diethylene glycol, 2-ethylhexanediol,1,4-cyclohexanediol, 1,2,6-hexanetriol, 1,3,5-hexanetriol,1,3-bis-(2-hydroxyethoxy)propane and the like. While such compounds arecommercially available, methods for synthesizing such compounds are wellknown in the art. Commercially available semicrystalline polyesterpolyols useful in the invention include, for example, Dynacoll 7130,7240, and 7360 (Creanova), Fomrez 66-32 (Crompton) and Rucoflex S-105-30(Bayer). Examples of polycarboxylic acids include phthalic acid,isophthalic acid, terephthalic acid, tetrachlorophthalic acid, maleicacid, dodecylmaleic acid, octadecenylmaleic acid, fumaric acid, aconiticacid, trimellitic acid, 3,3′-thiodipropionic acid, succinic acid, adipicacid, malonic acid, glutaric acid, pimelic acid, sebacic acid,cyclohexane-1,2-dicarboxylic acid, 1,4-cyclohexadiene-1,2-dicarboxylicacid, 3-methyl-3,5-cyclohexadiene-1,2-dicarboxylic acid and thecorresponding acid anhydrides, acid chlorides and acid esters such asphthalic anhydride, phthaloyl chloride and the dimethyl ester ofphthalic acid. Preferred polycarboxylic acids are the aliphatic andcycloaliphatic dicarboxylic acids containing about 14 or less carbonatoms and the aromatic dicarboxylic acids containing about 14 or lesscarbon atoms.

In various embodiments, the curable polymer is an epoxy resin. Epoxyresins may comprise epoxy group-containing monomers, prepolymers andpolymers and combinations thereof. Suitable epoxy group-containingresins particularly include those with 1 to 10, preferably 2 to 10 epoxygroups per molecule. “Epoxy groups”, as used herein, relates to1,2-epoxy groups (oxirane).

Typical epoxy group-containing resins are liquid, aromatic epoxycompounds. Examples include, without limitation, (poly)glycidyl ethers,usually obtained by reacting epichlorohydrin or epibromohydrin withpolyphenols in the presence of bases or (poly)glycidyl ethers of phenolformaldehyde (novolac) resins, alkyl-substituted phenol formaldehyderesins, phenol hydroxybenzaldehyde resins, cresol hydroxybenzaldehyderesins, dicyclopentadiene phenol resins anddicyclopentadiene-substituted phenol resins. Suitable polyphenolsinclude, without limitation, resorcin, brenzcatechin, hydroquinone,bisphenol A (2,2-bis(4-hydroxyphenyl)propane), bisphenol F(bis(4-hydroxyphenyl)methane), 1,1-bis(4-hydroxyphenyl)isobutane,4,4-dihydroxybenzophenone, 1,1-bis(4-hydroxyphenyl)ethane and1,5-hydroxynaphthalene. Also suitable are diglycidylether of ethoxylatedresorcin (DGER) and the diglycydidylethers of resorcin, brenzcatechin,hydroquinon, bisphenol, bisphenol A, bisphenol AP(1,1-bis(4-hydroxyphenyl)-1-phenylethane), bisphenol F, bisphenol K,bisphenol S, and tetramethylbiphenol.

Further suitable epoxy resins are known in the art and are for exampledescribed in Lee H. & Neville, K., Handbook of Epoxy Resins, McGraw-HillBook Company, newly edited version of 1982.

In various embodiments, the curable compositions contain the curablepolymer, for example the polyorganosiloxane (A), in an amount of 32 to97% by weight, particularly preferably in an amount of 40 to 70% byweight, based in each case on the total weight of the composition. If amixture of polymers, for example a mixture of polyorganosiloxanes, isused, the amounts relate to the total amount of polymers in thecomposition

The curable compositions contain as component (B) at least one cappedadhesion promoter of formula (I):

B—R¹¹—SiR¹² _(q)(OR¹³)_(3-q)   (II)

wherein

R¹¹ is a linear or branched alkylene group, optionally interrupted by aheteroatom, preferably selected from O, NR¹⁴, S and Si(R¹⁴)₂, preferablyC₁-C₁₀ alkylene, more preferably C₁ or C₃ alkylene;

each R¹² is independently selected from the group consisting ofhydrogen, halogen, amino, a substituted or unsubstituted alkyl, alkenyl,alkynyl, cycloaliphatic, aryl, heteroaryl, and heteroalicyclic group ora combination thereof;each R¹³ is independently selected from the group consisting of asubstituted or unsubstituted alkyl, alkenyl, alkynyl, or acyl group;each R¹⁴ is independently selected from the group consisting ofhydrogen, alkyl, alkenyl, alkynyl, cycloaliphatic, aryl, heteroaryl, andheteroalicyclic group or a combination thereof;q independently stands for 0, 1, or 2; andB is a nitrogen-containing group of formula (1)

—NR¹⁵R¹⁶   (1)

whereinR¹⁵ is selected from —Si(R¹⁷)₃;R¹⁶ is selected from —Si(R¹⁷)₃, hydrogen, a substituted or unsubstitutedalkyl, alkenyl, alkynyl, cycloaliphatic, aryl, heteroaryl, andheteroalicyclic group or a combination thereof; andeach R¹⁷ is independently selected from hydrogen, a substituted orunsubstituted alkyl, alkenyl, alkynyl, cycloaliphatic, or aryl group ora combination thereof; or wherein R¹⁵ and R¹⁶ combine to form togetherwith the nitrogen atom to which they are attached a group of formula—Si(R¹⁷)₂—R¹⁸—Si(R¹⁷)₂—, wherein R¹⁸ is a linear or branched alkylenegroup, preferably C₂ or C₃ alkylene.

The terms “blocked” and “capped” in relation to the compound of formula(I) are used interchangeably herein. Furthermore, the compound offormula (I) is herein referred to as a blocked/capped adhesion promoter.

Blocked”, as used herein in connection with the compounds of formula(I), refers to the fact that said compounds are derivatized such thatthe active compound is only released upon contact with water and/oroxygen.

In various embodiments of the compound (B), in the group of formula (1),R¹⁵ is —Si(R¹⁷)₃ and each R¹⁷ is preferably independently hydrogen,unsubstituted alkyl, more preferably C₁₋₄ alkyl, such as ethyl ormethyl, or alkenyl, such as vinyl. It can be preferred that no or onlyone R¹⁷ is hydrogen and the others are alkyl or alkenyl.

In various embodiments, R¹⁶ is hydrogen, alkyl, such as propyl ormethyl, substituted with —Si(R¹⁷)₃, or —Si(R¹⁷)₃, preferably —Si(R¹⁷)₃,with each R¹⁷ independently being unsubstituted alkyl, preferably methylor ethyl, more preferably methyl, or, alternatively, alkenyl, such asvinyl.

Generally, as already defined above, if one R¹⁷ is hydrogen, the otherR¹⁷ groups on the same silicon atom are preferably not hydrogen.Preferred groups for R¹⁵ and R¹⁶ include, but are not limited to,—SiH(CH₃)₂, —Si(CH₃)₂(CH═CH)₂, —Si(CH₃)₂(C₆H₅), and —Si(CH₃)₃. In suchembodiments, q may be 0 or 1, R¹¹ may be propylene, and R¹², if present,may be methyl and R¹³ may be methyl or ethyl, preferably ethyl.

In other preferred embodiments, R¹⁵ and R¹⁶ combine to form togetherwith the nitrogen atom to which they are attached a group of formula—Si(R¹⁷)₂-C₂₋₃ alkylene-Si(R¹⁷)₂—, in particular—Si(R¹⁷)₂—(CH₂)₂—Si(R¹⁷)₂—, with R¹⁷ being unsubstituted alkyl,preferably methyl or ethyl, more preferably methyl, or, alternativelyalkenyl, such as vinyl.

In various embodiments, each R¹² and R¹³ is independently selected frommethyl and ethyl, preferably each R¹³ is ethyl.

In various embodiments, R¹³ may be alkyl or substituted alkyl, such asamino alkyl. Preferred (amino)alkyl groups are C₁-C₆ alkyl groups,preferably linear alkyl groups, such as C₁-C₅ alkyl groups, includingethyl, n-propyl, n-butyl and n-pentyl, optionally with a terminal amino,alkylamino or dialkylamino group, preferably a N,N-di(C₁-C₄ alkyl)aminogroup, such as a N,N-dimethyl- or N,N-diethylamino group. Accordingly,R¹³ may be C₁-C₅ alkyl substituted with an amino group of the formula—NR²¹R²² with R²¹ and R²² independently being selected from hydrogen,methyl, and ethyl.

In various embodiments, at least one, preferably two, R¹⁷ may be alkenylor substituted alkyl, with substituted alkyl being for example alkoxy.

In various embodiments, the capped adhesion promoter is a silazane offormula (I) with q being 0, R¹¹ being methylene or propylene, preferablypropylene, each R¹³ being ethyl or methyl, preferably ethyl, and B beinga group of formula (1), wherein R¹⁵ is —Si(R¹⁷)₃ and R¹⁶ is hydrogen,alkyl substituted with —Si(R¹⁷)₃, or —Si(R¹⁷)₃, preferably —Si(R¹⁷)₃,and each R¹⁷ is independently alkyl, preferably methyl or ethyl, morepreferably methyl. In various alternative embodiments, at least one R¹⁷can be alkenyl, preferably vinyl.

In concrete embodiments, the adhesion promoter (B) is a compound offormula (I), wherein

-   -   (i) q is 0, R¹¹ is propylene, each R¹³ is ethyl or methyl,        preferably ethyl, R¹⁵ and R¹⁶ are —Si(R¹⁷)₃, and each R¹⁷ is        independently alkyl, preferably methyl or ethyl, more preferably        methyl. In various alternative embodiments, at least one R¹⁷ can        be hydrogen or alkenyl, preferably vinyl;    -   (ii) q is 0, R¹¹ is branched alkylene, such as isopentylene or        isohexylene, including dimethylbutylene, each R¹³ is ethyl or        methyl, preferably ethyl, R¹⁵ and R¹⁶ are —Si(R¹⁷)₃, and each        R¹⁷ is independently alkyl, preferably methyl or ethyl, more        preferably methyl. In various alternative embodiments, at least        one R¹⁷ can be hydrogen or alkenyl, preferably vinyl;    -   (iii) q is 0, R¹¹ is propylene, each R¹³ is dialkylaminoalkyl,        preferably N,N-di(C₁-C₄ alkyl)amino(C₁-C₆)alkyl, such as        N,N-dimethyl-amino-n-pentyl, N,N-dimethylamino-ethyl or        N,N-diethylaminoethyl, R¹⁵ and R¹⁶ are both —Si(R¹⁷)₃, and each        R¹⁷ is independently alkyl, preferably methyl or ethyl, more        preferably methyl; or    -   (iv) q is 0, R¹¹ is propylene, each R¹³ is methyl or ethyl,        preferably ethyl, R¹⁵ and R¹⁶ combine to form        —Si(R¹⁷)₂—CH₂—CH₂—Si(R¹⁷)₂—, and each R¹⁷ is independently        alkyl, preferably methyl or ethyl, more preferably methyl.

The curable compositions contain the capped adhesion promoter preferablyin an amount of about 0.1 to about 5% by weight, preferably 0.3 or 0.5to 2% by weight, based in each case on the total weight of thecomposition. If a mixture of capped adhesion promoters is used, theamounts refer to the total amount of such capped adhesion promoters inthe composition.

The curable compositions optionally comprise as component (C) at leastone curing catalyst.

In various embodiments, the curing catalyst may be a tin compound,preferably an organotin compound or an inorganic tin salt. Tin in thesetin compounds is preferably bivalent or tetravalent. Component (C) isadded to the composition particularly as a crosslinking catalyst.Suitable inorganic tin salts are, for example, tin(II) chloride andtin(IV) chloride. Organotin compounds (tin organyles) are usedpreferably as the tin compounds, however. Suitable organotin compoundsare, for example, the 1,3-dicarbonyl compounds of bivalent ortetravalent tin, for example, the acetylacetonates such asdi(n-butyl)tin(IV) di(acetylacetonate), di(n-octyl)tin(IV)di(acetylacetonate), (n-octyl)(n-butyl)tin(IV) di(acetylacetonate); thedialkyl tin(IV) dicarboxylates, for example, di-n-butyltin dilaurate,di-n-butyltin maleate, di-n-butyltin diacetate, di-n-octyltin dilaurate,di-n-octyltin diacetate, or the corresponding dialkoxylates, forexample, di-n-butyltin dimethoxide; oxides of tetravalent tin, forexample, dialkyltin oxides, such as, for example, di-n-butyltin oxideand di-n-octyltin oxide; and the tin(II) carboxylates such as tin(II)octoate or tin(II) phenolate.

Suitable furthermore are tin compounds of ethyl silicate, dimethylmaleate, diethyl maleate, dioctyl maleate, dimethyl phthalate, diethylphthalate, dioctyl phthalate, such as, for example, di(n-butyl)tin(IV)di(methyl maleate), di(n-butyl)tin(IV) di(butyl maleate),di(n-octyl)tin(IV) di(methyl maleate), di(n-octyl)tin(IV) di(butylmaleate), di(n-octyl)tin(IV) di(isooctyl maleate); anddi(n-butyl)tin(IV) sulfide, (n-butyl)₂Sn(SCH₂COO),(n-octyl)₂Sn(SCH₂COO), (n-octyl)₂Sn(SCH₂CH₂COO),(n-octyl)₂Sn(SCH₂CH₂COOCH₂CH₂OCOCH₂S), (n-butyl)₂—Sn(SCH₂COO-i-C₈H₁₇)₂,(n-octyl)₂Sn(SCH₂COO-i-C₈H₁₇)₂, and (n-octyl)₂Sn(SCH₂COO-n-C₈H₁₇)₂.

Preferably, the tin compound is selected from 1,3-dicarbonyl compoundsof bivalent or tetravalent tin, the dialkyltin(IV) dicarboxylates, thedialkyltin(IV) dialkoxylates, the dialkyltin(IV) oxides, the tin(II)carboxylates, and mixtures thereof.

Particularly preferably, the tin compound is a dialkyltin(IV)dicarboxylate, particularly di-n-butyltin dilaurate or di-n-octyltindilaurate.

Additionally or alternatively, other metal-based condensation catalystsmay be used, including, without limitation, compounds of titanium suchas organotitanates or chelate complexes, cerium compounds, zirconiumcompounds, molybdenum compounds, manganese compounds, copper compounds,aluminum compounds, or zinc compounds or their salts, alkoxylates,chelate complexes, or catalytically active compounds of the main groupsor salts of bismuth, lithium, strontium, or boron.

Further suitable (tin-free) curing catalysts are, for example,organometallic compounds of iron, particularly the 1,3-dicarbonylcompounds of iron such as, e.g., iron(III) acetylacetonate.

Boron halides such as boron trifluoride, boron trichloride, borontribromide, boron triiodide, or mixtures of boron halides can also beused as curing catalysts. Particularly preferred are boron trifluoridecomplexes such as, e.g., boron trifluoride diethyl etherate, which asliquids are easier to handle than gaseous boron halides.

Further, amines, nitrogen heterocycles, and guanidine derivatives aresuitable in general for catalysis. An especially suitable catalyst fromthis group is 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

Titanium, aluminum, and zirconium compounds, or mixtures of one or morecatalysts from one or more of the just mentioned groups may also be usedas catalysts.

Suitable as titanium catalysts are compounds that have hydroxy groupsand/or substituted or unsubstituted alkoxy groups, therefore titaniumalkoxides of the general formula

Ti (ORZ)₄,

where R^(z) is an organic group, preferably a substituted orunsubstituted hydrocarbon group having 1 to 20 C atoms, and the 4 alkoxygroups —OR^(z) are identical or different. Further, one or more of the—OR^(z) groups can be replaced by acyloxy groups —OCOR^(z).

Likewise suitable as titanium catalysts are titanium alkoxides in whichone or more alkoxy groups are replaced by a hydroxy group or halogenatoms.

Further, titanium chelate complexes can be used.

Aluminum catalysts can also be used as curing catalysts, e.g., aluminumalkoxides

Al(OR^(z))₃,

where R^(z) has the above meaning; i.e., it is an organic group,preferably a substituted or unsubstituted hydrocarbon group having 1 to20 C atoms and the three R^(z) groups are identical or different. In thecase of aluminum alkoxides as well, one or more of the alkoxy groups canbe replaced by acyloxy groups —OC(O)R^(z).

Further, aluminum alkoxides can be used in which one or more alkoxygroups are replaced by a hydroxy group or halogen atoms.

Of the described aluminum catalysts, the pure aluminum alcoholates arepreferred in regard to their stability to moisture and the curability ofthe mixtures to which they are added. In addition, aluminum chelatecomplexes are preferred.

Suitable as zirconium catalysts are, e.g.: tetramethoxyzirconium ortetraethoxyzirconium.

Diisopropoxyzirconium bis(ethyl acetoacetate), triisopropoxyzirconium(ethyl acetoacetate), and isopropoxyzirconium tris(ethyl acetoacetate)are used with very particular preference.

Further, zirconium acylates can be used, for example.

Halogenated zirconium catalysts can also be used.

Further, zirconium chelate complexes can also be used.

In addition, carboxylic acid salts of metals or also a mixture of anumber of such salts can be employed as curing catalysts, whereby theseare selected from the carboxylates of the following metals: calcium,vanadium, iron, zinc, titanium, potassium, barium, manganese, nickel,cobalt, and/or zirconium.

Of the carboxylates, the calcium, vanadium, iron, zinc, titanium,potassium, barium, manganese, and zirconium carboxylates are preferred,because they exhibit a high activity. Calcium, vanadium, iron, zinc,titanium, and zirconium carboxylates are particularly preferred. Ironand titanium carboxylates are very particularly preferred.

The curable compositions contain the curing catalyst preferably in anamount of from about 0.05 to 2% by weight, preferably 0.1 to 1.5% or 0.1to 0.5% by weight, based in each case on the total weight of thecomposition. If a mixture of different catalysts is used, the amountsrefer to the total amount in the composition.

The compositions of the invention may comprise moisture curable polymersand may then crosslink in the presence of moisture and in so doing curewith the formation of Si—O—Si bonds.

The molar ratio of the capped adhesion promoter and tin compound, ifpresent, may, in various embodiments, be adjusted that it is at least1:1, for example in the range of 1:1 to 50:1. This may help to assurethat the curable composition, on the one hand, has very high storagestability and, on the other, cures reliably and at a sufficient rateafter application in the presence of atmospheric moisture even at roomtemperature (23° C.).

The curable compositions can contain, apart from the components (A), (B)and optionally (C), one or more components that can be used toselectively influence specific properties of the curable compositionand/or the cured product.

These other components can be selected, for example, from the groupcomprising plasticizers, stabilizers, antioxidants, fillers, reactivediluents, drying agents, adhesion promoters besides the capped adhesionpromoters of formula (I), UV stabilizers, rheological aids, and/orsolvents. Of particular importance are typically plasticizers, fillers,and stabilizers, comprising antioxidants and UV stabilizers.

Preferably, the curable compositions therefore contain at least onefurther component.

The composition described herein can contain in addition up to about 20%by weight of conventional adhesion promoters (tackifiers). Suitable asadhesion promoters are, for example, resins, terpene oligomers,coumarone/indene resins, aliphatic petrochemical resins, and modifiedphenol resins. Suitable within the context of the present invention are,for example, hydrocarbon resins, as can be obtained by polymerization ofterpenes, primarily α- or β-pinene, dipentene, or limonene. Thesemonomers are generally polymerized cationically with initiation usingFriedel-Crafts catalysts. The terpene resins also include, for example,copolymers of terpenes and other monomers, for example, styrene,α-methylstyrene, isoprene, and the like. The aforesaid resins are used,for example, as adhesion promoters for contact adhesives and coatingmaterials. Also suitable are terpene-phenol resins, which are preparedby the acid-catalyzed addition of phenols to terpenes or rosin.Terpene-phenol resins are soluble in most organic solvents and oils andmiscible with other resins, waxes, and natural rubber. Also suitable asan additive in the aforesaid sense within the context of the presentinvention are the rosin resins and derivatives thereof, for example, theesters thereof.

Also suitable are silane adhesion promoters, particularly alkoxysilanes,with a (further) functional group such as, e.g., an amino group, amercapto group, an epoxy group, a carboxyl group, a vinyl group, anisocyanate group, an isocyanurate group, or a halogen. Examples areγ-mercaptopropyltrim ethoxysilane, γmercaptopropyltriethoxysilane,γ-mercaptopropylmethyldimethoxysilane,γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane,γ-glycidoxypropylmethyldimethoxysilane, β-carboxyethyltriethoxysilane,β-carboxyethylphenylbis(2-methoxyethoxy)silane,N-β-(carboxymethyl)aminoethyl-γ-aminopropyltrimethoxysilane,vinyltrimethoxysilane, vinyltriethoxysilane,γ-acroyloxypropylmethyltriethoxysilane,γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane,γ-isocyanatopropylmethyldiethoxysilane,γ-isocyanatopropylmethyldimethoxysilane,tris(trimethoxysilyl)isocyanurate, and γ-chloropropyltrimethoxysilane.

It is furthermore possible to include further adhesion promoters asidefrom the compounds of formula (I), with said adhesion promoters beingaminosilanes. Said aminosilanes may be selected from3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,aminomethyltrimethoxysilane, aminomethyltriethoxysilane,3-aminopropylmethyldiethoxysilane,(N-2-aminoethyl)-3-aminopropyltrimethoxysilane,(N-2-aminoethyl)-3-aminopropyltriethoxysilane,diethylenetriaminopropyltrimethoxysilane,phenylaminomethyltrimethoxysilane,(N-2-aminoethyl)-3-aminopropylmethyldimethoxysilane,3-(N-phenylamino)propyltrimethoxysilane,3-piperazinylpropylmethyldimethoxysilane,3-(N,N-dimethylaminopropyl)aminopropylmethyldimethoxysilane,tri[(3-triethoxysilyl)propyl]amine, tri[(3-trimethoxysilyl)propyl]amine,and the oligomers thereof, 3-(N,N-dimethylamino)propyltrimethoxysilane,3-(N,N-dimethylamino)-propyltriethoxysilane,(N,N-dimethylamino)methyltrimethoxysilane,(N,N-dimethylamino)methyltriethoxysilane,4-amino-3,3-dimethylbutyltrimethoxysilane and4-amino-3,3-dimetylbutyltriethoxysilane3-(N,N-diethylamino)propyltrimethoxysilane,3-(N,N-diethylamino)propyltriethoxysilane,(N,N-diethylamino)methyltrimethoxysilane,(N,N-diethylamino)methyltriethoxysilane,bis(3-trimethoxysilyl)propylamine, bis(3-triethoxysilyl)propylamin, andmixtures thereof, particularly preferably of3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,aminomethyltrimethoxysilane, aminomethyltriethoxysilane,3-(N,N-dimethylamino)propyl-trimethoxysilane,3-(N,N-dimethylamino)propyltriethoxysilane,(N,N-dimethylamino)methyltrimethoxysilane,(N,N-dimethylamino)methyltriethoxysilane,3-(N,N-diethylamino)propyltrimethoxysilane,3-(N,N-diethylamino)propyltriethoxysilane,(N,N-diethylamino)methyltrimethoxysilane,(N,N-diethylamino)methyltriethoxysilane,bis(3-trimethoxysilyl)propylamine, and bis(3-triethoxysilyl)propylamine.

In various embodiments, the compositions of the invention furthercomprise at least one aminosilane as described above, in particular oneof the tertiary aminosilanes. “Tertiary aminosilane”, as used herein,refers to an aminosilane wherein the nitrogen atom of the amino group iscovalently linked to three non-hydrogen residues. In variousembodiments, the aminosilane is selected from the group consisting of3-piperazinylpropylmethyldimethoxysilane, 3-(N,N-dimethylaminopropyl)aminopropylmethyldimethoxysilane,tri[(3-triethoxysilyl)propyl]amine, tri[(3-trimethoxysilyl)propyl]amine,and the oligomers thereof, 3-(N,N-dimethylamino)propyltrimethoxysilane,3-(N,N-dimethylamino)propyltriethoxysilane,(N,N-dimethylamino)methyltrimethoxysilane,(N,N-dimethylamino)methyltriethoxysilane,3-(N,N-diethylamino)propyltrimethoxysilane,3-(N,N-diethylamino)propyltriethoxysilane,(N,N-diethylamino)methyltrimethoxysilane,(N,N-diethylamino)methyltriethoxysilane,bis(3-trimethoxysilyl)propylamine, bis(3-triethoxysilyl)propylamin,4-amino-3,3-dimethylbutyltrimethoxy silane and4-amino-3,3-dimetylbuthyltriethoxy silane and mixtures thereof,particularly preferably of 3-(N,N-dimethylamino)propyltrimethoxysilane,3-(N,N-dimethylamino)propyltriethoxysilane,(N,N-dimethylamino)methyl-trimethoxysilane,(N,N-dimethylamino)methyltriethoxysilane,3-(N,N-diethylamino)propyltrimethoxysilane,3-(N,N-diethylamino)propyltriethoxysilane,(N,N-diethylamino)methyltrimethoxysilane,(N,N-diethylamino)methyltriethoxysilane.

It is conceivable that the viscosity of the curable composition is toohigh for certain applications. It can then be reduced in a simple andexpedient way usually by using a reactive diluent, without any signs ofdemixing (e.g., plasticizer migration) occurring in the cured mass.

Preferably, the reactive diluent has at least one functional group whichafter application reacts, e.g., with moisture or atmospheric oxygen.Examples of groups of this type are silyl groups, isocyanate groups,vinylically unsaturated groups, and polyunsaturated systems.

All compounds that can be mixed with the other components with areduction in viscosity and have at least one group reactive with thepolymer can be used as reactive diluents.

The viscosity of the reactive diluent is preferably less than 20,000mPas, particularly preferably about 0.1 to 6000 mPas, very particularlypreferably 1 to 1000 mPas (Brookfield RVT, 23° C., spindle 7, 10 rpm).

The following substances, for example, can be used as reactive diluents:polyalkylene glycols reacted with isocyanatosilanes (e.g., Synalox100-50B, DOW), carbamatopropyltrimethoxysilane, alkyltrimethoxysilane,alkyltriethoxysilane, such as methyltrimethoxysilane,methyltriethoxysilane, and vinyltrimethoxysilane (XL 10, Wacker),vinyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane,octyltrimethoxysilane, tetraethoxysilane, vinyldimethoxymethylsilane(XL12, Wacker), vinyltriethoxysilane (GF56, Wacker),vinyltriacetoxysilane (GF62, Wacker), isooctyltrimethoxysilane (IOTrimethoxy), isooctyltriethoxysilane (IO Triethoxy, Wacker),N-trimethoxysilylmethyl-O-methyl carbamate (XL63, Wacker),N-dimethoxy(methyl)silylmethyl-O-methyl carbamate (XL65, Wacker),hexadecyltrimethoxysilane, 3-octanoylthio-1-propyltriethoxysilane, andpartial hydrolysates of said compounds.

Further, the following polymers from Kaneka Corp. can also be used asreactive diluents: MS S203H, MS S303H, MS SAT 010, and MS SAX 350.

Silane-modified polyethers which derive, e.g., from the reaction ofisocyanatosilane with Synalox types can likewise be used.

Polymers that can be prepared from an organic framework by grafting witha vinylsilane or by reacting polyol, polyisocyanate, and alkoxysilanecan be used, furthermore, as reactive diluents.

A polyol is understood to be a compound that may contain one or more OHgroups in the molecule. The OH groups can be both primary and secondary.

Suitable aliphatic alcohols include, for example, ethylene glycol,propylene glycol, and higher glycols, as well as other polyfunctionalalcohols. The polyols can contain in addition other functional groupssuch as. e.g., esters, carbonates, or amides.

To prepare the preferred reactive diluents, the corresponding polyolcomponent is reacted in each case with an at least difunctionalisocyanate. Any isocyanate having at least two isocyanate groups maybasically be used as the at least difunctional isocyanate, but withinthe scope of the present invention, compounds with two to fourisocyanate groups, particularly with two isocyanate groups, aregenerally preferred.

Preferably, the compound present as the reactive diluent has at leastone alkoxysilyl group, whereby of the alkoxysilyl groups, the di- andtrialkoxysilyl groups are preferred.

Suitable as polyisocyanates for the preparation of a reactive diluentare, for tetramethoxybutane diisocyanate, 1,6-hexamethylene diisocyanate(HDI), cyclobutane-1,3-diisocyanate, cyclohexane-1,3 and -1,4diisocyanate, bis(2-isocyanatoethyl) fumarate, as well as mixtures oftwo or more thereof, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 2,4- and2,6-hexahydrotoluylene diisocyanate, hexahydro-1,3- or -1,4-phenylenediisocyanate, benzidine diisocyanate, naphthalene-1,5-diisocyanate,1,6-diisocyanato-2,2,4-trimethylhexane,1,6-diisocyanato-2,4,4-trimethylhexane, xylylene diisocyanate (XDI),tetramethylxylylene diisocyanate (TMXDI), 1,3- and 1,4-phenylenediisocyanate, 2,4- or 2,6-toluylene diisocyanate (TDI),2,4′-diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate, or4,4′-diphenylmethane diisocyanate (MDI), or the partially or completelyhydrogenated cycloalkyl derivatives thereof, for example, completelyhydrogenated MDI (H12-MDI), alkyl-substituted diphenylmethanediisocyanates, for example, mono-, di-, tri-, or tetraalkyldiphenylmethane diisocyanate and the partially or completelyhydrogenated cycloalkyl derivatives thereof, 4,4′-diisocyanatophenylperfluoroethane, phthalic acid bis-isocyanatoethyl ester,1-chloromethylphenyl-2,4- or -2,6-diisocyanate, 1-bromomethylphenyl-2,4-or -2,6-diisocyanate, 3,3-bis-chloromethyl ether-4,4′-diphenyldiisocyanate, sulfur-containing diisocyanates, as can be obtained byreacting 2 mol of diisocyanate with 1 mol of thiodiglycol ordihydroxydihexyl sulfide, the di- and triisocyanates of dimer and trimerfatty acids, or mixtures of two or more of the aforesaid diisocyanates.

Trivalent or higher valent isocyanates, as can be obtained, for example,by oligomerization of diisocyanates, particularly by oligomerization ofthe aforesaid isocyanates, can also be used as polyisocyanates. Examplesof such trivalent and higher-valent polyisocyanates are thetriisocyanurates of HDI or IPDI or mixtures thereof or mixedtriisocyanurates thereof, as well as polyphenylmethylene polyisocyanate,as can be obtained by phosgenation of aniline-formaldehyde condensationproducts.

Solvents and/or plasticizers can be used, in addition to or instead of areactive diluent, for reducing the viscosity of the curable composition.

Suitable as solvents are aliphatic or aromatic hydrocarbons, halogenatedhydrocarbons, ketones, ethers, esters, ester alcohols, keto alcohols,keto ethers, keto esters, and ether esters.

The composition described herein can furthermore contain hydrophilicplasticizers. These are used to improve the moisture absorption andthereby to improve the reactivity at low temperatures. Suitable asplasticizers are, for example, esters of abietic acid, adipic acidesters, azelaic acid esters, benzoic acid esters, butyric acid esters,acetic acid esters, esters of higher fatty acids having approximately 8to approximately 44 carbon atoms, epoxidized fatty acids, fatty acidesters and fats, glycolic acid esters, phosphoric acid esters, phthalicacid esters, linear or branched alcohols containing 1 to 12 carbonatoms, propionic acid esters, sebacic acid esters, sulfonic acid esters,thiobutyric acid esters, trimellitic acid esters, citric acid esters,and esters based on nitrocellulose and polyvinyl acetate, as well asmixtures of two or more thereof.

For example, of the phthalic acid esters, dioctyl phthalate, dibutylphthalate, diisoundecyl phthalate, or butylbenzyl phthalate is suitable,and of the adipates, dioctyl adipate, diisodecyl adipate, diisodecylsuccinate, dibutyl sebacate, or butyl oleate.

Also suitable as plasticizers are the pure or mixed ethers ofmonofunctional, linear or branched C₄₋₁₆ alcohols or mixtures of two ormore different ethers of such alcohols, for example, dioctyl ether(obtainable as Cetiol OE, Cognis Deutschland GmbH, Düsseldorf).

Endcapped polyethylene glycols are also suitable as plasticizers, forexample, polyethylene or polypropylene glycol di-C₁₋₄-alkyl ethers,particularly the dimethyl or diethyl ethers of diethylene glycol ordipropylene glycol, and mixtures of two or more thereof.

Suitable plasticizers are endcapped polyethylene glycols, such aspolyethylene or polypropylene glycol dialkyl ethers, where the alkylgroup has up to four C atoms, and particularly the dimethyl and diethylethers of diethylene glycol and dipropylene glycol. An acceptable curingis achieved in particular with dimethyldiethylene glycol also under lessfavorable application conditions (low humidity, low temperature).Reference is made to the relevant technical chemistry literature forfurther details on plasticizers.

Also suitable as plasticizers are diurethanes, which can be prepared,for example, by reacting diols, having OH end groups, withmonofunctional isocyanates, by selecting the stoichiometry such thatsubstantially all free OH groups react. Optionally excess isocyanate canthen be removed from the reaction mixture, for example, by distillation.A further method for preparing diurethanes consists of reactingmonofunctional alcohols with diisocyanates, whereby all NCO groups arereacted if possible.

In various embodiments, the plasticizer may be a polydimethylsiloxanedifferent from (A), particularly a PDMS that does not have terminalgroups of formula (I).

In various embodiments, the curable composition comprises at least oneplasticizer, for example a polydimethylsiloxane.

The curable compositions contain the plasticizer preferably in an amountof 1 to 50% by weight, preferably in an amount of 10 to 40% by weight,particularly preferably in an amount of 20 to 30% by weight, based ineach case on the total weight of the composition. If a mixture ofplasticizers is used, the amounts refer to the total amount ofplasticizers in the composition.

Preferably, the curable composition contains at least one stabilizer,selected from antioxidants, UV stabilizers, and drying agents.

All conventional antioxidants may be used as antioxidants. They arepreferably present up to about 7% by weight, particularly up to about 5%by weight.

The composition herein can contain UV stabilizers, which are preferablyused up to about 2% by weight, preferably about 1% by weight. Theso-called hindered amine light stabilizers (HALS) are particularlysuitable as UV stabilizers. It is preferred within the context of thepresent invention if a UV stabilizer is employed, which carries a silylgroup and is incorporated into the end product during crosslinking orcuring. The products Lowilite 75 and Lowilite 77 (Great Lakes, USA) areparticularly suitable for this purpose. Further, benzotriazoles,benzophenones, benzoates, cyanoacrylates, acrylates, sterically hinderedphenols, phosphorus, and/or sulfur can also be added.

It is often useful to stabilize the compositions in regard topenetrating moisture by means of drying agents in order to increase thestorability (shelf life) still further.

Such an improvement in storability can be achieved, for example, byusing drying agents. All compounds that react with water with theformation of a group inert to the reactive groups present in thepreparation are suitable as drying agents and thereby undergo thesmallest possible changes in their molecular weight. Furthermore, thereactivity of the drying agents to moisture penetrating into thepreparation must be higher than the reactivity of the groups of thesilyl group-bearing polymer of the invention present in the preparation

Isocyanates, for example, are suitable as drying agents.

Advantageously, however, silanes are used as drying agents. For example,vinylsilanes such as 3-vinylpropyltriethoxysilane, oxime silanes such asmethyl-O,O′,O″-butan-2-one-trioximosilane orO,O′,O″,O′″-butan-2-one-tetraoximosilane (CAS Nos. 022984-54-9 and034206-40-1) or benzamidosilanes such asbis(N-methylbenzamido)methylethoxysilane (CAS No. 16230-35-6) orcarbamatosilanes such as carbamatomethyltrimethoxysilane. The use ofmethyl-, ethyl-, or vinyltrimethoxysilane, tetramethyl- ortetraethylethoxysilane is also possible. Vinyltrimethoxysilane andtetraethoxysilane are particularly suitable in terms of cost andefficiency.

Also suitable as drying agents are the aforesaid reactive diluents,provided they have a molecular weight (Mn) of less than about 5000 g/moland have end groups whose reactivity to penetrated moisture is at leastas high as, preferably higher than, the reactivity of the reactivegroups of the polymer used according to the invention.

Lastly, alkyl orthoformates or alkyl orthoacetates can also be used asdrying agents, for example, methyl or ethyl orthoformate or methyl orethyl orthoacetate.

The compositions generally contain about 0 to about 6% by weight ofdrying agent.

The composition described herein can additionally contain fillers.Suitable here are, for example, chalk, lime powder, precipitated and/orpyrogenic (fumed) silica, zeolites, bentonites, magnesium carbonate,diatomaceous earth, alumina, clay, tallow, titanium oxide, iron oxide,zinc oxide, sand, quartz, flint, mica, glass powder, and other groundmineral substances. Organic fillers can also be used, such as, forexample, carbon black, graphite, wood fibers, wood flour, sawdust,cellulose, cotton, pulp, cotton, wood chips, chopped straw, and chaff.Short fibers such as glass fibers, glass filament, polyacrylonitrile,carbon fibers, Kevlar fibers, or polyethylene fibers may also be added.Aluminum powder is also suitable as a filler.

The pyrogenic (fumed) and/or precipitated silica preferably have a BETsurface area of 10 to 90 m²/g. When they are used, they do not cause anyadditional increase in the viscosity of the composition of theinvention, but contribute to strengthening the cured composition.

It is likewise conceivable to use pyrogenic and/or precipitated silicawith a higher BET surface area, advantageously with 100 to 250 m²/g,particularly 110 to 170 m²/g, as a filler. Because of the higher BETsurface area, the same effect, e.g., strengthening of the curedpreparation, can be achieved at a smaller weight proportion of silicicacid. Further substances can thus be used to improve the compositiondescribed herein in terms of other requirements.

Suitable further as fillers are hollow spheres having a mineral shell ora plastic shell. These can be, for example, hollow glass spheres whichare obtainable commercially under the trade names Glass Bubbles®^(.)Plastic-based hollow spheres, e.g., Expancel® or Dualite®, aredescribed, for example, in EP 0 520 426 B1. They are made up ofinorganic or organic substances and each have a diameter of 1 mm orless, preferably 500 μm or less.

Fillers that impart thixotropy to the preparations are preferred formany applications. Such fillers are also described as rheologicaladjuvants, e.g., hydrogenated castor oil, fatty acid amides, orswellable plastics such as PVC. In order to be readily squeezable out ofa suitable dispensing device (e.g., a tube), such preparations possess aviscosity from 3000 to 15,000, preferably 40,000 to 80,000 mPas, or even50,000 to 60,000 m Pas.

The fillers are preferably used in an amount of 1 to 80% by weight,particularly preferably 2 to 20% by weight, and very particularlypreferably 5 to 10% by weight, based in each case on the total weight ofthe composition. Of course, mixtures of a number of fillers can also beused. In this case, the quantitative data naturally refer to the totalamount of filler in the composition.

While the compositions of the invention have been described herein inparticular with reference to silicone polymers and SMPs, especiallypolysiloxanes, it is understood that the invention also encompassescompositions with other types of curable polymers. It is understood thatfor such compositions the additional (optional) components may beadapted or replaced, with such modification and selection being wellwithin the routine capabilities of the skilled practitioner in thefield.

The preparation of the curable composition can take place by simplemixing of the polymer (A), the capped adhesion promoter (B), theoptional catalyst (C), and optionally the other ingredients. This cantake place in suitable dispersing units, e.g., a high-speed mixer. Inthis case, preferably, care is taken that the mixture does not come intocontact with moisture as far as possible, which could lead to anundesirable premature curing. Suitable measures are sufficiently knownand comprise, for example, working in an inert atmosphere, possiblyunder a protective gas, and drying/heating of individual componentsbefore they are added.

The compositions of the invention can be used as an adhesive or sealingor coating material.

The composition can be used, for example, as an adhesive, sealant,coating, and for the production of molded parts. A further field ofapplication for the compositions is the use as a plugging compound, holefiller, or crack filler. The use as a sealant may be preferred.

The compositions are suitable, inter alia, for bonding plastics, metals,glass, ceramic, wood, wood-based materials, paper, paper-basedmaterials, rubber, and textiles, for gluing floors, and for sealingbuilding elements, windows, wall and floor coverings, and joints ingeneral. In this case, the materials can be bonded to themselves or asdesired to one another.

The following examples serve to explain the invention, but the inventionis not limited thereto.

EXAMPLES Example 1

The comparison composition C1 and the compositions E1 and E2 accordingto the invention were prepared by mixing the raw materials listed inTable 1. The formulations differ in the type of the adhesion promoterused. The polyorganosiloxane (A) was obtained in a first step bycombining the siloxane with the vinyl tris(ethyl lactato)silane.

TABLE 1 E1 E2 C1 C2 Parts by Parts by Parts by Parts by Raw materialsweight weight weight weight α,ω-dihydroxy-terminated 52.18  52.18  52.7152.58 polydimethylsiloxane with a viscosity of 80,000 cST Vinyltris(ethyl lactato)silane 4.92 4.92 4.97 4.95 Plasticizer (α,ω-dimethyl-33.04  33.04  33.39 33.29 terminated Polydimethylsiloxane with aviscosity of 1,000 cST) Highly dispersed silicic acid 7.28 7.28 7.357.33 3-(N,N-dimethyl- — — 0.5 0.5 amino)propyltrimethoxysilane Cappedamino silane A 2.01 2.01 — — Capped amino silane B — 0.39 — 0.673-Aminopropyltrimethoxysilane 0.39 — 0.9 0.5 Tin compound (dioctyltindilaurate 0.18 0.18 0.18 0.18 (DOTL))Capped amino silane A is a compound of formula (I), wherein q is 0, R¹¹is propylene, each R¹³ is ethyl and B is a group of formula (1) whereinR¹⁵ and R¹⁶ are both —Si(R¹⁷)₃ and each R¹⁷ is methyl.Capped amino silane B is a ketimine that is similar to compounds offormula (I), wherein q is 0, R¹¹ is propylene, each R¹³ is ethyl but Bis —N═C(isobutyl)(methyl) (isobutylmethylimino).

Polymer (A) was formed from the α,ω-Dihydroxy-terminatedpolydimethylsiloxane and the vinyl tris(ethyl lactato)silane in aprevious step and then combined with the adhesion promoters and thecuring catalyst.

The prepared formulations were subjected to curing performance tests asfollows:

Determination of Skin-over time (SOT): Skin-over time (SOT) is definedas the time required for the material to form a non-tacky surface film.The determination of the skin over time is carried out according to DIN50014 under standard climate conditions (23+/−2° C., relative humidity50+/−5%). The temperature of the sealant must be 23+/−2° C., with thesealant stored for at least 24 h beforehand in the laboratory. Thesealant is applied to a sheet of paper and spread out with a putty knifeto form a skin (thickness about 2 mm, width about 7 cm). The stopwatchis started immediately. At intervals, the surface is touched lightlywith the fingertip and the finger is pulled away, with sufficientpressure on the surface that an impression remains on the surface whenthe skin formation time is reached. The skin-over time is reached whensealing compound no longer adheres to the fingertip. The skin-over time(SOT) is expressed in minutes.

Measurement of Shore A hardness: Shore A hardness was measured accordingto ISO 868.

Determination of the depth of cure (DOC): A strip of the material with aheight of 10 mm (+/−1 mm) and width of 20 mm (+/−2 mm) was applied overa plastic foil (PP) using a Teflon spatula. After storing the sample for24 hours at normal conditions (23+/−2° C., relative humidity 50+/−5%), asection of the strip was cut off and the thickness of the cured layerwas measured with a caliper. The depth of cure after 24 hours isexpressed in millimeters.

Assessment of the mechanical properties (tensile test): The Tensile testdetermines the breaking force, elongation at break and yield stressvalue (e-module), according to DIN 53504. Deviation from the norm:dumbbell specimens with the following dimensions were used: thickness2+/−0.2 mm; bar width 10+/−0.5 mm; bar length approx. 45 mm; totallength 9 cm. The tests took place at normal conditions (23+/−2° C.,relative humidity 50+/−5%). The measurement was carried out after 7 daysof curing. Procedure: the prepolymer mixture (formulation) was spread onan even surface forming a film with a thickness of 2 mm. The film wasallowed to cure under normal conditions (see above) for seven days, andthen the dumbbell specimen was punched out. Three specimens were usedfor each determination. The test was carried out under normalconditions. The test specimens have to be at the same temperature atwhich the measurement will take place. Before the measurement, thethickness of the test specimens is determined at least at threedifferent positions, at the middle and at the extremes, with a caliper.The mean value is introduced in the measuring software. The testspecimens are clamped into the tensile tester so that the longitudinalaxis coincides with the mechanical axis of the tensile tester andcomprises the largest possible surface of the rod heads, withoutclamping the middle bar. Then the dumbbell is stretched to <0.1 MPa witha rate of 50 mm/min.. Then, the force-elongation curve is recorded witha line speed of 50 mm/min. Evaluation: The following values aredetermined: breaking force in [N/mm²] elongation at break in [%] andmodulus at 100% elongation in [N/mm²].

Peel Test:

If possible and needed, substrate (test panel) is cleaned prior toapplication using a suitable solvent. A strip of the material with aheight of 10 mm (+/−1 mm) and width of 20 mm (+/−2 mm) was applied overthe substrate using a Teflon spatula. The sample was stored for 7 daysat normal conditions (23+/−2° C., relative humidity 50+/−5%). The curedmaterial was cut back for at least 15mm with a shape blade and the beadpulled by hand. Failure mode was recorded as following:

✓ ⇔ Cohesion failure (CF) or alternatively cohesive/adhesive failure

˜ ⇔ Adhesion failure (AF) with “strong resistance”

x ⇔ Adhesion failure.

TABLE 2 Properties of compositions prior to storage (directly aftermixing) E1 E2 C1 C2 SOT (min) 13 7 5 10 Shore A 1 d 12 12 12 12 Shore A7 d 17 16 20 14 cure through 4.44 3.86 3.66 3.21 (mm in 24 h) tack 24 hTack free Tack free Tack free Tack free ADHESION PMMA ~ x ~ ~Aluminum/Elox ✓ ✓ ✓ ✓ Brass ✓ ✓ ✓ ✓ Glass ✓ ✓ ~ ✓ Concrete ~ ✓ ~ ✓Modulus at 0.32 0.26 0.32 0.23 100% Elongation at 651.8 701.5 587.9613.7 break

TABLE 3 Properties of compositions after storage (8 weeks; 40° C., 80%humidity) E1 C1 SOT (min) 24 24 Shore A 1 d 2 8 Shore A 7 d 17 curethrough 3.36 4.02 (mm in 24 h) tack 24 h Tack free Tack free ADHESIONPMMA ~ x Aluminum/Elox ✓ ~ Brass ✓ ✓ Glass ✓ ✓ Concrete ~ x Modulus at0.2 0.33 100% Elongation at 678.4 583.5 break

The results show that the compositions of the invention have a betteradhesion and significantly higher storage stability compared to thecomparative composition.

1. A curable composition comprising (A) at least one curable polymer;(B) at least one capped adhesion promoter of formula (I):B—R¹¹—SiR¹² _(q)(OR¹³)_(3-q)   (I) wherein R¹¹ is a linear or branchedalkylene group, optionally interrupted by a heteroatom; each R¹² isindependently selected from the group consisting of hydrogen, halogen,amino, a substituted or unsubstituted alkyl, alkenyl, alkynyl,cycloaliphatic, aryl, heteroaryl, and heteroalicyclic group or acombination thereof; each R¹³ is independently selected from the groupconsisting of a substituted or unsubstituted alkyl, alkenyl, alkynyl, oracyl group; each R¹⁴ is independently selected from the group consistingof hydrogen, alkyl, alkenyl, alkynyl, cycloaliphatic, aryl, heteroaryl,and heteroalicyclic group or a combination thereof; q independentlystands for 0, 1, or 2; and B is a nitrogen-containing group of formula(1)—NR¹⁵R¹⁶   (1) wherein R¹⁵ is selected from —Si(R¹⁷)₃; R¹⁶ is selectedfrom —Si(R¹⁷)₃, hydrogen, a substituted or unsubstituted alkyl, alkenyl,alkynyl, cycloaliphatic, aryl, heteroaryl, and heteroalicyclic group ora combination thereof; and each R¹⁷ is independently selected fromhydrogen, a substituted or unsubstituted alkyl, alkenyl, alkynyl,cycloaliphatic, or aryl group or a combination thereof; or wherein R¹⁵and R¹⁶ combine to form together with the nitrogen atom to which theyare attached a group of formula —Si(R¹⁷)₂—R¹⁸—Si(R¹⁷)₂—, wherein R¹⁸ isa linear or branched alkylene group; and (C) optionally at least onecuring catalyst.
 2. The curable composition according to claim 1,wherein the capped adhesion promoter is a silazane of formula (I) with qbeing 0, R¹¹ being methylene, n-propylene or n-butylene, each R¹³ beingmethyl, ethyl or C₁-C₅ alkyl substituted with an amino group of theformula —NR¹⁹R²⁰ with R¹⁹ and R²⁰ independently being selected fromhydrogen, methyl, and ethyl, and B being a group of formula (1), whereinR¹⁵ is —Si(R¹⁷)₃ and R¹⁶ is hydrogen, alkyl substituted with —Si(R¹⁷)₃or —Si(R¹⁷)₃, and each R¹⁷ is independently alkyl.
 3. The curablecomposition according to claim 1, wherein (i) the amount of polymer (A)is from about 32 to about 97% by weight, relative to the total weight ofthe composition; and/or (ii) the amount of capped adhesion promoter (B)is from about 0.1 to about 5% by weight, relative to the total weight ofthe composition; and/or (iii) the amount of the curing catalyst, ifpresent, is from about 0.05 to 2% by weight, relative to the totalweight of the composition.
 4. The curable composition according to claim1, wherein the at least one curable polymer (A) is selected from thegroup consisting of silane-modified polymers, silicones, polyurethanes,and epoxides.
 5. The curable composition according to claim 4, whereinthe at least one curable polymer is polydimethylsiloxane (PDMS).
 6. Thecurable composition according to claim 4, wherein the curable polymer(A) comprises at least one terminal group of the formula (II):-A-Si(R¹)_(m)(R²)_(n)(R³)_(3-(m+n))   (II) wherein: A is a bond, —O— ora linear, branched or cyclic divalent group selected from hydrocarbonresidues having 1 to 12 carbon atoms, alkylene, arylene, oxyalkylene,oxyarylene, siloxane-alkylene, siloxane-arylene, ester, amine, glycol,imide, amide, alcohol, carbonate, urethane, urea, sulfide, ether or aderivative or combination thereof; each R¹ is independently selectedfrom the group consisting of hydrogen, halogen, amino, oximino, asubstituted or unsubstituted alkyl, alkenyl, alkenyloxy, alkynyl,alkylnyloxy, cycloaliphatic, cycloaliphatic-O-, aryl, aryloxy,heteroaryl, heteroaryloxy, heteroalicyclic, heteroalicyclicoxy, acyl,acyloxy group or a combination thereof; each R² is independently a groupof the general formula (2):—O—Y—COOR⁴   (2) wherein Y is a substituted or unsubstituted(hetero)aromatic group having 4 to 14 ring atoms, a substituted orunsubstituted saturated or partially unsaturated 4- to 14-membered(hetero)cyclic group or —(C(R⁵)₂)_(o)—; R⁴ is a substituted orunsubstituted alkyl, alkenyl, alkynyl, cycloaliphatic, aryl, heteroaryl,and heteroalicyclic group or a combination thereof; each R⁵ isindependently selected from the group consisting of hydrogen, asubstituted or unsubstituted alkyl, alkenyl, alkynyl, cycloaliphatic oraryl group; and o is an integer from 1 to 10; each R³ independently is agroup of the general formula (3):—O—Y—CONR⁶R⁷   (3) wherein Y is as defined above; R⁶ is selected fromthe group consisting of hydrogen, a substituted or unsubstituted alkyl,alkenyl, alkynyl cycloaliphatic, aryl, heteroaryl, and heteroalicyclicgroup or a combination thereof or R⁷; R⁷ is a group of the generalformula (4):—R⁸—SiR⁹ _(p)(OR¹⁰)_(3-p)   (4) wherein R⁸ is an alkylene group,optionally interrupted by a heteroatom; each R⁹ is independentlyselected from the group consisting of hydrogen, halogen, amino, asubstituted or unsubstituted alkyl, alkenyl, alkynyl, cycloaliphatic,aryl, heteroaryl, and heteroalicyclic group or a combination thereof;each R¹⁰ is independently selected from the group consisting of asubstituted or unsubstituted alkyl, alkenyl, alkynyl, or acyl group;each p independently stands for 0, 1, or 2; m is independently 0, 1 or2; and n is independently 1, 2, or 3, wherein the sum n+m is a maximumof
 3. 7. The curable composition according to claim 6, wherein A is abond, —O— or a linear or branched divalent group of the formula—(CH₂)₁₋₁₀—(Si(Alk)₂—O—Si(Alk)₂)₁₋₁₀—(CH₂)₁₋₁₀, or a derivative thereof,with Alk being unsubstituted C₁₋₁₀ alkyl.
 8. The curable compositionaccording to claim 6, wherein each R¹ independently of one anotherstands for an alkyl group having 1 to 10 carbon atoms, or for an alkenylgroup having 2 to 10 carbon atoms, or for an aryl group having 6 to 10carbon atoms, or for an aryloxy group having 6 to 14 carbon atoms, orfor an acyloxy group having 2 to 10 carbon atoms, or for amino; and/oreach R² independently of one another stands for a group of the formula(2), wherein R⁴ stands for a substituted or unsubstituted alkyl grouphaving 1 to 10 carbon atoms, and Y is a substituted or unsubstitutedaromatic group having 6 carbon ring atoms, or —(C(R⁵)₂)_(o)—, wherein ois 1 and one of the R⁵ groups is hydrogen and the second R⁵ group is asubstituted or unsubstituted alkyl group having 1 to 10 carbon atoms. 9.The curable composition according to claim 6, wherein the sum n+m is 3.10. The curable composition according to claim 6, wherein the groupSi(R¹)_(m)(R²)_(n)(R³)_(3-(m+n)) in formula (I) is selected from methylbis(ethyl lactato)silane, ethyl bis(ethyl lactato)silane, phenylbis(ethyl lactato)silane, vinyl bis(ethyl lactato)silane, tri(ethyllactato)silane, methyl bis(ethyl salicylato)silane, ethyl bis(ethylsalicylato)silane, phenyl bis(ethyl salicylato)silane, vinyl bis(ethylsalicylato)silane, tri(ethyl salicylato)silane, methyl bis(diethylmalato)silane, ethyl bis(diethyl malato)silane, phenyl bis(diethylmalato)silane, vinyl bis(diethyl malato)silane, tri(diethylmalato)silane and mixtures thereof.
 11. The curable compositionaccording to claim 6, wherein the sum of n+m is a maximum of 2; and eachR³ independently of one another stands for a group of the formula (3),wherein Y is a substituted or unsubstituted aromatic group having 6carbon ring atoms or —C(R⁵)₂)_(o)—, wherein o is 1 and one of the R⁵groups is hydrogen and the second R⁵ group is a substituted orunsubstituted alkyl group having 1 to 10 carbon atoms, R⁶ representshydrogen, a substituted or unsubstituted alkyl group having 1 to 10carbon atoms, and R⁷ represents a group of the formula (4), where R⁸ isa C1-10 alkylene group, each R⁹ independently of one another stands fora substituted or unsubstituted alkyl group having 1 to 10 carbon atoms,and each R¹⁹ independently of one another stands for a substituted orunsubstituted alkyl group having 1 to 10 carbon atoms; and p is 0 or 1.12. The curable composition according to claim 1, wherein the curingcatalyst is a tin compound selected from 1,3-dicarbonyl compounds ofbivalent or tetravalent tin, dialyltin(IV) dicarboxylates,dialkyltin(IV) dialkoxylates, dialkyltin(IV) oxides, tin(II)carboxylates, and mixtures thereof.
 13. The curable compositionaccording to claim 1, further comprising any one or more additionalingredients selected from the group consisting of plasticizers, fillers,bases, and adhesion promoters different from the capped adhesionpromoter (B).
 14. The curable composition according to claim 1, whereinthe composition further comprises at least one adhesion promoterdifferent from the capped adhesion promoter, wherein said additionaladhesion promoter is selected from the group consisting of3-(N,N-dimethylamino)propyltrimethoxysilane,3-(N,N-dimethylamino)propyltriethoxysilane,(N,N-dimethylamino)methyltrimethoxysilane,(N,N-dimethylamino)methyltriethoxysilane,3-(N,N-diethylamino)propyltrimethoxysilane,3-(N,N-diethylamino)propyltriethoxysilane,(N,N-diethylamino)methyltrimethoxysilane,(N,N-diethylamino)methyltriethoxysilane,bis(3-trimethoxysilyl)propylamine, bis(3-triethoxysilyl)propylamine,4-amino-3,3-dimethylbutyltrimethoxy silane and4-amino-3,3-dimetylbuthyltriethoxy silane.
 15. An adhesive, sealing, orcoating material comprising the curable composition according toclaim
 1. 16. Cured reaction products of the curable compositionaccording to claim
 1. 17. An article comprising a surface and curedreaction products of the curable composition according to claim 1 bondedto the surface.